Mitsubishi MU-2Mitsubishi MU-2

Overview

Written by Richard Shine, a former Air Force Colonel and pilot, a member of the MU-2 Aircraft Owners and Pilots Association, a Board Member of the National Business Aviation Association, and a long-time member of AOPA.

The Mitsubishi MU-2 represents a fantastic opportunity for pilots to operate a very dependable, rugged, reliable, fast and safe aircraft, and to do so at a very competitive cost. This airplane began life as a clean sheet design in the 1960s at a time when most other aircraft manufacturers simply bolted turboprop engines on the wings of piston airplanes. It’s a tribute to the engineers at Mitsubishi that this airframe is as relevant today as it was when it was designed almost fifty- years ago. Many MU-2s have been upgraded with modern avionics and have all the bells and whistles that are found on new aircraft rolling off the assembly line, but on a proven airframe and at a fraction of the price of a new aircraft.

Just looking at the MU-2 on the ground inspires confidence. It simply looks rugged on the ramp. From the compact size to the very sturdy landing gear (which was copied from the F-104 Starfighter), the MU-2 exudes trust. This aircraft weighs more than the new light jets, resulting in an exceptionally robust airframe. The proven Honeywell TPE-331 engine, the Dash 10 version, powers the MU-2, which is capable of 1000 horsepower per side - although it is de-rated on this installation. This engine has a TBO of over 5000 hours, much more than the competition, and it is more miserly on fuel as well. The engine drives an eight-foot diameter propeller. This power train delivers excellent climb capability and high-speed cruising, approaching the speed of today’s very light jets. Even the older MU-2s with less power perform extremely well. The MU-2 can easily operate in the relatively empty mid-twenty-thousand-foot altitudes, and unlike the VLJs, it does not need to climb into the higher Flight Levels to achieve its advertised range. Cruise speeds range from the 280s to in excess of 310 knots true, depending upon altitude, temperature, model, and weight.

On preflight inspection, a new MU2 pilot might ask the instructor, “Where are the ailerons?” The answer goes back to the clean sheet design mentioned above. Mitsubishi surveyed corporate operators, asking what characteristics they wanted in an airplane for corporate transportation. The overwhelming desire expressed by potential operators was speed, with short field capability a close second. Unfortunately, it is difficult to achieve both of these objectives, since, to some extent, they are mutually exclusive.

The engineers at Mitsubishi, a very cleaver bunch indeed, decided that to achieve the high cruise speeds by using a smaller wing than the competitors along with the ability to “grow” the wing with an effective flap system for slow speed operations such as short field landings and takeoffs. With flap extension, the surface area of the wing increases by around 21%, thus lowering the wing loading and the stall speeds. Typical approach speeds range between 101 and 109 KCAS.

The simple if not ingenious solution caused Mitsubishi to do away with the ailerons, which provided more room on the wing for a full span double-slotted fowler flap. Since fowler flaps extend along the entire wing trailing edge, roll control was achieved by using a spoiler system mounted on top of the wing. Spoiler technology is hardly unique, as it is also found on the B-52 bomber, the A-4 attack aircraft, many modern corporate jets, nearly all airliners, and even some modern light aircraft. Further, designers often use spoilers to augment traditional ailerons to assist with roll control. Not only are spoilers very effective for achieving roll control, they have additional benefits traditional aileron systems lack, such as eliminating adverse yaw and improving roll rates above those which can be achieved with comparable aileron controlled aircraft.

Continuing on our preflight walk around, we notice a small tab on the trailing edge of the flaps. This electrically actuated miniature flap provides roll trim capability. Unlike traditional aileron trim tabs; the MU-2 trim ailerons trim the entire wing, so that no spoiler deflection is necessary with a properly trimmed airplane. On the wing tips are fuel tanks much like those found on the Lear series of aircraft. These tanks provide for extended range and are found on all MU-2s. The large vertical tail and rudder provide plenty of directional control in cross wind and engine out situations.

The MU-2 comes in two basic varieties: short body and long body models. There are other distinctions and improvements made over the years, the biggest of which is the switch from three blade propellers to four. The long body MU-2 can comfortably accommodate 8-11 passengers, depending upon configuration, but with the same wing and engine as the short body, it is a few knots slower. The short body aircraft generally seats seven, but there are several aircraft configured with a side facing bench seat that holds eight. Pilots who perhaps have only flown the short body MU-2 once or twice might report that it is difficult to land. This is simply not true. The placement of the landing gear aft of the center of gravity, plus the location of a heavy battery in the nose, requires a different technique to land than the long body, but a few sessions with a qualified MU-2 instructor makes short body landings a non-event.

In some past MU-2 reviews, there has been much mention of engine out performance. A great deal of erroneous information regarding this issue still circulates among the uninformed. The reality is simply that the MU-2 performs much like any other airplane in its class when confronted with an “engine out” situation. The skills necessary to successfully manage such an event are easily learned and practiced in both the simulator and the airplane. The reliability of the Honeywell TPE-331 engine is legendary. However, though rare, all engines can fail, and if a loss of an engine happens, the power available from a turbine engine makes a successful outcome a near certainty if the aircraft is flown by the book and within its flight manual envelope. I have been flying the MU-2 for over fifteen-years, and while I have never experienced an actual in-flight engine failure, I have experienced hundreds of them, mostly on take-off, in the simulator. These events require that the failed engine be secured, the aircraft properly trimmed and configured, and thought given to making a safe single engine landing, just as is required in any twin engine aircraft under similar circumstances. Once the above steps are completed, the MU-2 flies quite well on one engine.

The MU-2 systems were designed more like a transport aircraft than a light business airplane. Across the board, they are very robust. The fuel system is straight forward, with the engines feeding off the wing tanks located above them, and all other fuel replacing the fuel used from those tanks. It is very difficult to mismanage fuel in an MU-2 and there is no fuel cross-feed or unusable fuel in an engine out condition. The useable fuel capacity on the four-bladed Solitaire and Marquise models is 403 gallons … the older models carry a bit less. The electrical system in later models has a heavy-duty dual system, which practically precludes a total electrical failure in this aircraft. Earlier models have a single bus system, similar to other aircraft of that era. There are no hydraulic systems (except for brakes). The landing gear and flap systems are electric, have proven to be very reliable, and many operators comfortably fly this airplane into and out of unimproved airstrips. The pressurization, climate control, and anti/deice systems have also proven quite reliable over many years.

The safety record of any airplane is, of course, of extreme importance to those operating and flying it, as well as those contemplating doing so. The MU-2, when properly maintained and flown within its designed flight envelope, in accordance with the POM and Flight Manual, is one of the safest airplanes in its class. Prior to 2006, the MU2 had a higher accident rate than it has today, but even then, it was pretty much in the middle of the pack when compared to others in its category. A close look at most of the accidents across the MU-2s history will show that the vast majority of those accidents were not the fault of the airplane. Notwithstanding, the FAA did an exhaustive study of the MU-2 and its operation in 2005. The aircraft was given a clean bill of health, with many very positive comments about the MU-2 expressed by the FAA test pilots. This study resulted in the issuance of an SFAR, which mandated standardized training programs for both in-airplane training and simulator-based training at SimCom in Orlando, Florida. Further, requirements were added that specified how often this training was given, and at what level every pilot entered their training rotation, which was based on their currency or past-pilot-in-command experience in the MU-2.

Training is mandatory on an annual basis. This SFAR took effect in February 2007 - however many MU-2 pilots got the jump on the training and completed the initial cycle long before the required date. I feel that this SFAR was the driving force behind the very low accident rate the MU-2 has experienced since 2006. Every year since then, the MU2 has enjoyed the lowest accident rate of any airplane in its class. One seldom mentioned benefit to this reduction in the accident record has been a reduction in the cost of insurance.

Another important consideration that should be explored when contemplating the purchase of an aircraft is the support provided by the manufacturer. One would think that obtaining parts and service on an aircraft that has been out of production since 1985 would be very difficult. Quite the opposite is true for the MU-2. Mitsubishi Heavy Industries of America, Inc. (MHIA) maintains an office in Dallas and is committed to providing a level of support that exceeds most if not all current aircraft manufacturers as measured by annual product support surveys conducted by Aviation International News (AIN). MHIA maintains a new parts stock of commonly used parts, and can manufacture any part not in its stock. Mitsubishi’s support of this aircraft is enhanced by its contract with Turbine Aircraft Services of Addison Texas (TAS). TAS has well in excess of thirty-years experience with the MU-2. The MU-2 professionals there oversee the four domestic and two foreign factory service centers, provide training oversight, interface with MU-2 customers, and assist with MHIAs vender and engineering programs. They also assist MHIA in dealing with the FAA, including assisting on the recent SFAR.

One of the most surprising support programs for this airplane is the bi-annual PROP seminar. PROP stands for Pilot’s Review of Proficiency, and has been held every other year since 1994 at three or four locations around the country. The program consists of two days filled lectures and Q and A sessions covering different subjects ranging from accident reviews (lately material to discuss has been hard to come by), engine operations, best practices, and numerous other issues of interest to the MU-2 community. The PROP seminars are very well attended and are open to anyone with an interest in the aircraft, not just MU2 owners or pilots. MHIA provides all of the study materials, meals, and even a great cocktail party. The only cost to participants is the hotel and transportation. What other aircraft manufacturer does this?

In conclusion, if you are in the market for an aircraft that can carry 7-11 persons, can fly in excess of 1000 nautical miles, and do so at 300 knots, it behooves you to take a very close look at the MU2. In the fifteen years I have owned one, I have only had to cancel two trips due to maintenance. That is a standard of reliability that few aircraft can meet. It is not at all uncommon for this airplane to go from one 100-hour inspection to the next without seeing the inside of a maintenance facility. The rugged, reliable, and redundant systems in the MU2 are rarely found on other aircraft in its class. The acquisition price for a clean low time MU2 is a fraction of the price for a very light jet, and the performance is nearly the same. Finally, there is another unique and little known feature in the MU2 world there is a special comradery of MU2 owners and operators. We enjoy bi- annual fly-ins, meeting together at the PROP seminars and the MU2 activities at the annual NBAA Convention, as well as a very active on line blog that is filled with all kinds of information regarding the care and feeding of an MU2. In fact, many of the contributors on line have helped others investigate and eventually purchase this fine aircraft. The safety record, which the MU2 has enjoyed since the implementation of the SFAR, truly rounds out the desirability of owning one of these outstanding aircraft.

Performance Summary

From the compact size to the very sturdy landing gear (which was copied from the F-104 Starfighter), the MU-2 exudes trust. This aircraft weighs more than the new light jets, resulting in an exceptionally robust airframe. The proven Honeywell TPE-331 engine, the Dash 10 version, powers the MU-2, which is capable of 1000 horsepower per side - although it is de-rated on this installation. This engine has a TBO of over 5000 hours, much more than the competition, and it is more miserly on fuel as well. The engine drives an eight-foot diameter propeller. This power train delivers excellent climb capability and high-speed cruising, approaching the speed of today’s very light jets. Even the older MU-2s with less power perform extremely well. The MU-2 can easily operate in the relatively empty mid-twenty-thousand-foot altitudes, and unlike the VLJs, it does not need to climb into the higher Flight Levels to achieve its advertised range. Cruise speeds range from the 280s to in excess of 310 knots true, depending upon altitude, temperature, model, and weight.